How can I dye my dirty blonde hair black temporarily?

Just use a spray on. Trust me, you won't need many cans. I used one can of spray dye on three different long haired friends and myself before I ran out. One spray really does saturate your hair.

By the way, Locks of Love takes hair that's dyed dark, as long as it's not lightened with bleach. So even if you permanently dyed it black, they would take it, as dyeing it doesn't damage it as much as people think. Not as much as bleaching, anyway.

You SHOULD use "Roux Fanciful" temporary color- it washes out right away- it's a silver and pink bottle you can get it a Walmart. After you wash your hair you put it on your hair then style as usual. It has the consistency of kool-aid but it is process free, takes a minute to do and will not damage or stain your hair, it will stain your clothes, however. It also comes in mouse, but I can't find it where live except for at Sallys.

you might want to research this first but my friend's a dirty blonde and she uses the hair spray-paint. It's temporary (washable) so as soon as you get tired of it, it can be washed out. I haven't seen any damage but I don't want you to have any issues with it. Look it up and maybe that's what's right for you.

Browse the hair colour aisle. There are temporary formulas. I think Loreal makes a product that comes in fun colours that washes out in about 8 washes.